To realize integrated electromechanical devices with higher performance, instead of conventional electromagnetic actuators, piezoelectric actuators consisting of single crystals with a polarization-inverted layer have been studied for application with new electromechanical devices. Bending actuators for miniaturization and electrical drive methods for quick response were proposed, and contact phenomena were examined experimentally for high reliability. The following results were obtained.1. The formation of a LiNbO_3 polarization-inverted layer and the fabrication technique of the actuators were improved. A power-saving precision actuator with no hysteresis and no creep was developed.2. The defect of electrical contact due to oxidation or contamination in the atmosphere containing silicone was investigated. The effect on an electrode surface membrane and electric resistance of a heat treatment and a surrounding area atmosphere was studied. Moreover, the change of resistance due to surf
… Moreace impurities on the electrode caused by repeated contact was examined.3. To design new electromechanical actuators using a piezoelectric crystal, a computer simulation technique using a three-dimensional finite element method was improved. The results of the numerical analysis for displacement, resonant frequency, and electromechanical coupling coefficient were experimentally confirmed.4. A piezoelectric actuator with a integrated displacement sensor was proposed and examined to evaluate electrical contact phenomena such as an insulation destruction voltage and a locking phenomena.5. A servo accelerometer using a LiNbO_3 bending actuator was proposed and its potential was experimentally confirmed as a highly sensitive sensor in a frequency range of less than 1Hz.6. A proximity sensor utilizing an evanescent acoustic field formed by the LiNbO_3 bending vibrator with a polarization-inverted layer is proposed. It was demonstrated that when an object approached the surface of the vibrator, resonance frequency of the bending vibrator decreased sharply. Less